After a particularly good putting display, 1991
Masters Champion Ian Woosnam was once
quoted as saying that his performance on the
greens was all down to an evening’s practice
putting on his snooker table. Which gave me an
idea. A perfectly true surface, no grain, no pitch
marks...no excuses! What can the green baize
teach us about putting? Let’s rack ’em up

Analysis by Dr Paul Hurrion

Before you can work on the finer points of your
set-up and stroke, it’s vital that you have the ability
to ‘see’ and relate to a perfectly straight line to
the hole. So one of the very first things that I do
with a new pupil is challenge his or her perception
of a straight putt. And you’d be surprised at
the results, even among tour players.

Cue the snooker table! As you see here, I
have set up a simple test from 10 feet (you can
do this yourself with a line of balls on a putting
green or at home on the carpet). Placing the
brown, blue, pink and black on their respective
spots, I have lined up the cue-ball in balk, to create
a dead straight line down the table. (When
you practice this on a green, it’s a good idea to
use a chalk line to give yourself a perfect line of
reference. Indoors I use a builder’s laser – you
can pick up both of these products cheaply at the
hardware store.)

With the straight line of balls in place, the challenge
is to address the cue ball and take ‘dead
aim’ at the nearest ball (i.e. brown), just as if I
were aiming to strike it face on. I focus on squaring
the putter-face to the brown ball and, when
satisfied with my set-up, I look up to focus on the
next ball, the blue. What do I see? Does the line
of balls still appear straight? Well, not really…
and I feel the need to adjust my putter alignment
to the blue ball. Moving my focus further down
the table, to the pink and black balls, do I feel I
should realign my putter? Well yes… but I know
all the balls are aligned correctly?

What sense does it make to feel the need to
align the clubface differently for straight putts of 2
feet (to the brown ball), 5ft (blue), 7ft (pink) and
9ft (black) all down the same line?
What is happening?

The answer is that, according to their position
relative to the line we are looking down, our eyes
provide differing information to the brain as we
turn our heads and focus further away.
The length of the snooker table, with the use
of the brown, blue, pink and black spots, enables
me to place the balls in a perfectly straight line.
All you snooker players out there know that it’s
pretty easy to see a straight line when you are in
position, eyes low to the table. But what happens
when you stand up to a putting posture, taking
your position to the side of the ball?
And what happens when you then swivel your
head to scan the line to the hole? Do the balls
still appear in a straight line?!

GO OUT AND TEST yourself. Create a dead
straight line of balls into a hole, and then, once in
posture, just sway gently back and forth over the
ball you are addressing and focus on each of the
balls in turn as you swivel your head to check
alignment. The line will appear to curve, either
gently left-to-right or right-to-left, and, according
to where your focus lies, that is where you will
aim your putt. It’s no exaggeration to say that 9
times out of 10 I get the same reaction with all
golfers I teach – and I’m including tour players.

Clearly, the perception of the line is at odds
with reality, and if that’s your experience on the
greens you either (1) address the anomaly or (2)
continue to aim putts inaccurately. Which would
you prefer? Good answer... you’d like to address
the problem, and so your goal is to try to ensure
you align the putterface square to the target line,
irrespective of distance.

Matching perception with reality

The first step with the vast majority of players I
coach is to use my Quintic Putting Mirror to
assess the position of a player’s eye line in order
to match perception with reality – i.e. to identify
where they see a straight line at set-up.

As demonstrated on the snooker table, some
see a straight putt with their eyes parallel to the
target line (right above), the majority adopt a
position with the eyes just inside the target line
(middle) and in a few cases a player sees a
straight putt with their eyes outside the line (left).

On the snooker table, there is only one position
where the putter-face is square to all four of
the coloured balls, not four positions. I’m well
aware that putter-face direction accounts for over
90% of the ball’s starting line, so I need to find
the position over the ball where my eyes and
brain are in unison to achieve this.

To correct this most fundamental of alignment
issues, you have to accept that you will need to
adjust your posture and eye line over the object
ball at address – hopefully, only slightly, until you
see that line of balls as running true.

Here’s the bit you have rarely thought about:
once you have adjusted your eye position (and
with it your posture) you then must have both the
length and lie of your putter checked and, most
likely, tweaked to ‘fit’ this correct set-up position.
This is one of the most critical elements in the
whole process of becoming a better putter; look
at the angle of the shaft (above) to see what I
mean about length and lie!

For example, if your eyes are inside the line,
your putter will need to be longer and flatter, your
eyes outside, your putter will be shorter and
more upright. Speak to your local PGA
Professional for advice and invest in this
improvement!

You can easily use a putting mirror by yourself
to achieve the optimum eye position over the ball
and, contrary to popular opinion, that is not necessarily
directly above it.

Once you have found your position, mark the
mirror with a Sharpie so that every time you use
the mirror in practise you are working from the
same correct position. Hit putts. Do your eyes
remain in the same position after the ball has
been struck? The simple fact here is that it is all
about YOU as an individual. So do the research:
find out where YOU see the straight line, where
YOUR eyes need to be to see that straight line.
Once you have that information, you can begin
to practice with real purpose, and ingrain consistent
alignment factors into your routine.

The effect of side spin on a putt

The ability to influence the spin
critical in snooker – damaging on
the putting green

I am often asked ‘does side spin have an effect
on the path of the ball during putting?’ The short
answer is ‘yes’. A longer answer has been arrived
at courtesy of the The Quintic Ball Roll System I
have developed to analyse spin and roll accurately
during putting. I often see measurements of
over 30rpm of sidespin on a putt. Is this enough
to make an 8 foot putt miss the hole? Potentially
yes. Again, the snooker table can help me to
explain.

Spin doctor: striking the cue ball either side of the vertical axis line (illustrated with a dashed line in the left hand
graphic) enables a skilful snooker player to curve the path of the ball, such as would be necessary to strike the red
in this example. In planning the outcome of the shot, consideration would also be given to the reaction of the cue
ball following contact with the object ball (as illustrated below), all of which goes to explain the difficulty of the
game and the skill necessary to navigate the table. And, just as it is possible to create sidespin with a snooker ball,
so a golf ball is susceptible if struck off centre with a putter, just as in the full game – with consequences!

The game of snooker requires a lot of skill and
precision, players use many techniques to be successful.
In principle, the simplest shot in snooker
would be where the white cue ball, the object ball
(the coloured ball aimed at) and the pocket are
lined up perfectly in a straight line, with nothing
obstructing the path of the balls. We can all pot
this shot (well, everyone except Jonathan
Yarwood, who’s rubbish at snooker!) as long as
the cue ball is struck with the correct force (i.e. not
so little that the object ball would not reach the
pocket, but not too much that the cue ball would
follow the object ball into the pocket). This shot
requires the player to hit the cue ball directly in the
centre and follow through along the aiming
line...simple!

However, in game situations, most shots are
not this easy and require other techniques to
adapt to the situation. One example is where
another coloured ball is blocking the direct path of
the cue ball (as per the diagram above). In this
situation, the player can employ a technique
which creates side spin. Side spin is achieved by
striking the cue ball on either side of the vertical
plane (i.e. either left or right of the centre line displayed
by the dashed line in the graphic).

When the cue ball is struck directly on the centre
line, it will move in a straight line determined
by the point of aim of the cue ball. However, if
struck left or right of this centre line, the ball will
respond by moving off line right or left respectively,
and the proportion by which the ball is deflected
off a straight line path is determined by the
force and direction the cue strikes the ball.

This deviation from a straight line to a curved
path can be explained by the axes of rotation.
The spin is not as simple as the ball just rotating
clockwise or anticlockwise if viewed from above.
Due to friction between the ball and the baize, the
cue ball also rolls (just like a golf ball). As the ball
rolls, the orientation of this side spin axis changes
in relation to the initial position causing sideways
motion due to the reaction forces caused by the
friction between the table and the moving ball
(Newton’s Third Law).

When considering the example above, where
the direct line from the cue ball to the object ball is
partially obstructed, we must consider what happens
later on in the shot, not just the deviation
immediately after cue impact. Just as the cue ball
moved off the straight line path when first struck,
in time the cue ball will come back towards this
straight line path, and will even continue to veer
off the direct line in the opposite direction if given
enough distance.

The degree of side spin imparted on a snooker
ball can be as much as 500 rpm, if the cue impact
moves further away laterally from the centre line.

However, as the amount of side spin increases,
consequently so too does the degree of deflection
away from the direct line. It is important to
remember that just as you don’t want to hit the
ball down the centre line, similarly it is important
not to hit the cue ball too near the edge, as this
will result in a ‘miscue’ whereby the cue tip slides
around the side of the ball, and the cue ball
deflects off its intended line (pass the chalk!).

Bearing all this in mind, it is becoming clearer
why side spin is so complicated and hard to master.

And while unwanted side spin in snooker
could be regarded as a ‘nuisance’, adding an
extra variable to consider during a shot, the ability
to manipulate spin is a skill that separates better
players, allowing them to control and position the
cue ball around the table at will.

Another scenario whereby the effect of side
spin on a cue ball is important is when it comes to
considering the rebound off the cushion. When a
cue ball is hit with side spin down the length of the
table, there is no difference in speed compared to
if the ball was struck down it’s centre line, as it is
assumed the ball only makes ‘point’ contact with
the table. However, side spin is known to affect
both the rebound speed and the rebound angle of
the cue ball (Mathavan, S. et al., 2009) changing
the way the ball bounces off the cushion. The essential
at the highest level, and clearly adds to the
difficulty of a shot.

A neutral strike produces a
pure roll, the cue ball rebounding off the
cushion on exactly the same path at
which it approached it. In putting, the
quality of the stroke will determine the
roll and the spin that is applied to the
ball – swing the putter in-to-out and you
create hook spin, out-to-in and you will
impart cut spin. Both of these faults will
cause the ball to deviate after initial
bounce/skid as it rolls on the green

If a cue ball strikes a cushion at 90 degrees
without any form of side spin, it will rebound
directly along its line of approach. Additionally,
with no side spin, if the ball strikes the cushion at
a 30 degree angle, it will rebound at 30 degrees
and so on (see graphic above left). However, this
changes with side spin, as can be seen below.
This use of sidespin changes the direction of
the cue ball later on in the shot. After it hits the
object ball and deflects onto the cushion, the
sidespin is still in effect and the object ball
rebounds from contact with the cushion at an
abnormal angle.

In conclusion, side spin is used extensively in
snooker, be it intentional or not. A lot of variables
impact on the success of the shot, and it takes a
lot of time and practise to master the technique.
However, when this is achieved, it is a very useful
skill to possess to improve difficult situations.

So, going back to the original question, does
sidespin have an effect on the path of a golf ball
during putting? In short, yes! In the example you
see here (above), I am hitting a putt from the
blue spot, the mid point on the table, 6 feet to the
end cushion. I have deliberately created 30rpm
of hook spin, swinging the putter from in-to-out
(left hand image) and the angle at which the ball
rebounds is approximately 20 degrees away
from me. In the right-hand image, I have created
30rpm of cut spin (this time cutting across the
ball from out-to-in), resulting in the ball rebounding
20 degrees back towards me. Would such a
deviation away from a neutral stroke be enough
to make an 8-foot putt miss the hole?

Accomplished snooker
players use left- or righthand
sidespin to influence the
rebound angle of both cue
and object ball off the cushion.
Such a skill is vital when it
comes to break-building –
but less attractive with the
putter if you want to enjoy
consistent results rolling the
ball on your chosen line

Potentially, yes. As the two examples highlight
here, sidespin is still present on the golf ball over
six feet of its journey down the table. That sidespin,
however, is present only until TRUE ROLL
is achieved. What is the definition of True Roll?

To illustrate this, let me start by hitting the cue
ball dead centre – i.e. no top spin, no ‘bottom’
spin and no side spin. The ball starts by sliding
along the surface. Gradually it will start to rotate
because friction slows down the bottom of the
ball but not the top. The harder the ball is hit, the
further it will go before rotation starts to occur.
When it has stopped skidding or spinning then
true roll is achieved.

True Roll is when the horizontal velocity of the
ball equals the angular velocity of the ball.
As soon as the golf ball contacts the putting
surface, the friction on the ball will cause it to
start to over-spin, however this is not PURE
over-spin at this point. It can take the best part of
four feet out of a 10 foot putt for some tour players
to achieve pure roll. However, with optimal
launch characteristics, it is possible to achieve
true roll within 10-20% of the length of the putt.

Cochran and Stobbs (1968) indicate that a
putted golf ball will be in a state of pure rolling
after travelling approximately 20% of the total
length of the putt. However, this is a generalisation
and it depends on both the loft of the putter
and on the nature of the impact as a golf ball can
initially be given top spin or bottom spin.

Scientific research from Oxford University
(oxfordcroquet.com) states that “When a ball is
struck it starts moving by sliding over the grass.
As it travels the friction between the ball and the
grass causes it to start rolling until the rate of
rolling is matched to its progress across the
grass, that is, there is no sliding. The velocity of
the rolling ball travels at roughly 84% of the
velocity of the sliding ball struck with equal force.”

The point of true roll or zero skid.

Looking for a True Roll: A neutral strike on
the cue ball produces pure roll across the
baize; in putting, the best putters in the
world work on returning the putter-face
squarely to the equator of the golf ball to
achieve a neutral strike

The amount of sidespin imparted on the ball
still has an impact until the point of true roll has
been achieved. Even 20 rpm (quite a small
amount of side spin / rotation) can influence the
direction of the golf ball as it lands and makes
contact with the green and afterwards. Once you
are up to 50-60 rpm it most certainly influences
the ball. There is also a degree of rifle spin that is
imparted on the golf ball. Using 1000 frames-per-second (fps) video, the effect can be seen upon
landing and whilst the ball is still skidding until it
reaches true roll. Add in grass texture, slope,
grain and these can influence the starting line of
a putt with and without side spin. The influence
becomes more noticeable the shorter the putt.
Many players with a specific hook or cut stroke
will be subconsciously accounting for this in their
reading of greens.

So while sidespin can be useful in snooker it
has no place on the putting green. That is why
we all strive to achieve a square strike with the
putter running through the intended line. Any mismatch
between path and face will result in sidespin.

In addition, striking the ball out of the toe or
heal will create unwanted side-spin.

Launch Angle / Centre Strike

One of my key fundamentals is for the player
to create a centre strike: i.e. the centre of
gravity of the putter head should make contact
with the centre of the golf ball. I love this
visual: imagine you are trying to tap the drawing
pin into the golf ball (above left). Typically,
the golfer thinks of a mis-strike as a pull or
push through impact, causing the drawing pin
to be hit struck with a glancing blow. The same
cannot be said for an ascending blow (i.e. a positive
rise angle). Many coaches encourage their
pupils to actively hit up on the golf ball but any
amount of rise angle will also cause a glancing
blow for the drawing pin.

‘Tap, tap, tap it in!’
For a centre strike and a pure
roll, the sweet spot on the putterface
makes contact squarely with
the equator of the ball. The visual
of tapping a drawing pin into the
ball is a great one to take with
you out onto the golf course, as
it promotes the desired acceleration
into the ball and thus a positive
stroke; one that is more likely
to start the ball rolling on the
chosen line to the hole

TOPSPIN

Creating top spin with a putter is seen as a key
ingredient for success, with club manufactures
creating face technologies to help create the production
of topspin.

When relating this to snooker, the topspin shot
is typically used when attempting to open a pack
of reds. As the name suggests, topspin is produced
by striking the upper part of the cue ball
(as per image and graphic at right).

Just as it is important to make initial contact
with the cue ball above the centre, it is also as
important to follow-through correctly. A correct
strike will cause the ball to spin with forward
momentum (in the same direction as its linear
motion). The aim of this type of shot is to enable
the cue ball to travel further after impacting the
object ball due to the extra momentum gained
from the forward spinning motion, ultimately
increasing the distance the ball travels along the
table. This extra distance comes from the acceleration
of the cue ball immediately after collision
with the object ball. The collision, although reducing
the linear velocity of the cue ball, does not
affect its angular velocity, and thus the top spin
generated at cue contact is converted back into
linear velocity by the action of the sliding force
(Mathavan, S. et al., 2009).

In relation to the degree of topspin imparted
on the cue ball, it depends where upon on the
ball the cue impacts and with how much force.
The higher you strike above the centre line on
the cue ball, the greater the topspin produced
(Kumar, A., 1999). However, it is important to
note that there still has to be precision in the
point of contact with the cue ball. Too high and it
is easy for the cue to slide over the top of the
cue ball, resulting in a miscue, and even slightly
too far either side of the vertical plane running
through the centre of the ball will result in the production
of side spin, adding a further degree of
variability to the shot.

In the image of the putter tapping a drawing
pin into the ball’s equator (left), the middle of the
putter face is striking the very centre of the ball.
This is the desired strike. A lot of people conciously
try to hit up on the ball (i.e. swinging the
putter low to high), striking the underside of the
ball in an attempt to create the topspin. The
attack angle of the club and the dynamic loft of
the putter at impact create the topspin. In some
cases this might be as much as 150rpm of topspin,
which can cause the ball to ‘jump’ (not on
the first bounce but on the second, which is often
higher than the first!)

Think of a forehand shot in tennis, the ball
kicks and bounces higher as a result of the larger
topspin values. In an ideal world I am looking for
between 40/50rpm of topspin immediately off the
putter face. Too much and the ball is prone to
jump, too little and it will skid...

BACKSPIN

Another type of shot used in snooker involves
backspin. This form of spin is where the cue ball
rotates in the opposite direction to that in which it
is travelling, i.e. rotation backwards. Backspin is
achieved by striking the cue ball anywhere below
the centre line.

The stun or screw shot is perhaps the
most dramatic in snooker, achieved by
striking severely down on the lower half of
the ball; in putting, backspin can unwittingly
be achieved via common causes of
too high a launch angle, which include:
• Too much dynamic loft at impact
• Breaking the wrists (‘flipping’) just before
impact
• Having the ball too far forward in the
stance
• A putter with too much static loft
• Centre of Gravity of the putter head
below the centre (equator) of the golf ball

There are two purposes of putting backspin
on a cue ball; to either make the cue ball stop
dead after impact with the object ball (not easy to
achieve), or make the cue ball travel back the
way it came after contact with the object ball (the
‘screw’ shot). This is a technique which allows
the player to position the cue ball ready for the
next shot. In order to complete this shot successfully,
the player must take into account two factors;
the distance between the cue ball and the
object ball, and the speed of the cue ball. The
value of the backspin imparted on the cue ball is at its maximum immediately after cue contact,
and dissipates as the ball travels towards the
object ball. For the cue ball to travel back the
way it came, it must have enough angular
momentum from the initial backspin produced to
overcome the normal forward momentum. The
effect of the rolling frictional force between the
cue ball and the table is what provides the force
to initiate movement in the opposite direction to
the white ball’s initial movement.

As with executing other types of spin,
although it is important to strike the cue ball low
in order to impart backspin on it, the player must
be careful not to impact it too low, or the cue ball
will jump.

Backspin in putting is often the result of too
much dynamic loft at the point of impact, if the
launch angle is too high (above 2 degrees), the
ball will launch into the air (even at 4 mph), high
above the grass and bounce as it moves
towards the hole.

Another variable with potential to cause and
affect backspin is the face technology of the putter,
a relatively new phenomenon which is now a
major marketing angle. A lot of research and
development has been invested by the club
manufactures looking at reducing backspin at the
point of impact. While the ball is skidding or even
bouncing as a result of being launched into the
air, it has a greater chance of being deflected off
line by either the side (hook or cut) spin or imperfections
in the green. The ball will eventually get
to TRUE ROLL (the same as a seven iron bump
and run), but it will take much longer to achieve
this. The frictional force between the ball and
grass is the key here. Keep the golf ball in contact
with the grass at all times for an even declaration
of the golf ball. This is required for pace
control – after all the majority of three putts are
caused by poor pace control, rather than poor
green reading.

FACE & PATH OF CLUB

The edge of the table provides a perfect visual
key for path alignment. A straight edge or a
Putting Mirror can do the same. Face or Path –
the much more important of the two is putter face
angle. The breakdown is that approximately 90%
of the ball’s initial direction is determined by the
face angle at impact and only approximately 10%
is a result of the path the putter is following. The
two together determine the horizontal direction of
the ball and also if there is any hook or cut spin
applied to the ball. Even though path is 10%, I would still be looking for a gentle arc on the backswing
and through swing (no loop during transition).
The edge of the table provides a great visual.
It’s great practice holing putts on the snooker
table, running the golf ball (or even snooker ball)
along the edge of the cushion. More realistically, I
urge you to use a chalk line and hole putts using
it as your point of reference, running the blade
back and through on a gentle arc.

Down the rail: using a square edge as a
reference helps you to identify the true
inside-to-inside path of a good stroke.
On the green, use a chalk line or a piece
of 4x2 to give you the same feedback

CONCLUSION

There are no excuses for a miss on the snooker
table – no wind, no grain, dead flat surface!
During practice, each putt you hit needs a purpose
or a consequence. If not you are wasting
your time. Factors such as alignment of the putter
face, path of the putter, launch angle, speed,
impact location, grip pressure, forward or backwards
rotation, hook or cut spin, grain, spike
marks, slope and even wind can play a significant
part. The question I ask the players I coach
is simple: do you know the difference between a
good putt and a poor putt? Without feedback on
the launch conditions of each putt it becomes
very difficult to answer this question but without a
shadow of a doubt consistency is key. Focus on
a square strike with your (fitted) putter along an
actual (not perceived) straight target line and you
can start to learn when you’ve hit a good one.